---
title: "pageControllerWillStartLiveTransition(_:)"
framework: appkit
role: symbol
role_heading: Instance Method
path: "appkit/nspagecontrollerdelegate/pagecontrollerwillstartlivetransition(_:)"
---

# pageControllerWillStartLiveTransition(_:)

This message is sent when the user begins a transition.

## Declaration

```swift
@MainActor optional func pageControllerWillStartLiveTransition(_ pageController: NSPageController)
```

## Parameters

- `pageController`: The page controller.

## Discussion

Discussion This message is sent when the user begins a transition whether via a swipe gesture of one of the page controller’s target-action navigation methods.

## See Also

### Transition Notification

- [pageControllerDidEndLiveTransition(_:)](appkit/nspagecontrollerdelegate/pagecontrollerdidendlivetransition(_:).md)
- [pageController(_:didTransitionTo:)](appkit/nspagecontrollerdelegate/pagecontroller(_:didtransitionto:).md)